Radiation and Dose-densification of R-CHOP in Aggressive B-cell Lymphoma With Intermediate Prognosis: The UNFOLDER Study

Radiotherapy in younger patients with advanced aggressive B-cell lymphoma-long-term results from the phase 3 R-MegaCHOEP trial

The role of consolidative radiotherapy (RT) for patients with aggressive B-cell lymphoma has not been fully elucidated. The R-MegaCHOEP trial investigated the use of high-dose chemotherapy and rituximab with subsequent autologous stem cell transplantations compared to conventional immunochemotherapy (R-CHOEP) for high-risk patients up to 60 years. The study protocol included RT for patients with bulky (maximum diameter ≥7.5 cm) or extranodal disease. Two-hundred sixty-one patients were analyzed, 120 of whom underwent RT. The most frequently irradiated regions were mediastinum (n = 50) and paraaortic (n = 27). Median RT dose was 36 Gray in median fractions of 1.8 Gray. Acute toxicities were mostly mild to moderate, with only 24 and 8 grade 3 and 4 toxicities reported during RT. Patients with bulky disease who received RT showed significantly better 10-year EFS, PFS and OS (EFS: 64% vs. 35%; p < 0.001; PFS 68% vs. 47%; p = 0.003; OS: 72% vs. 59%; p = 0.011). There was no significant increase in secondary malignancies with the use of RT. RT administered for consolidation of bulky disease after immunochemotherapy improved the prognosis of young high-risk patients with aggressive B-cell lymphoma and should be considered part of first-line therapy. The trial was registered with ClinicalTrials.gov, number NCT00129090.

Genetic Characterization of Primary Mediastinal B-Cell Lymphoma: Pathogenesis and Patient Outcomes

PURPOSE

Primary mediastinal large B-cell lymphoma (PMBCL) is a rare aggressive lymphoma predominantly affecting young female patients. Large-scale genomic investigations and genetic markers for risk stratification are lacking.

PATIENTS AND METHODS

To elucidate the full spectrum of genomic alterations, samples from 340 patients with previously untreated PMBCL were investigated by whole-genome (n = 20), whole-exome (n = 78), and targeted (n = 308) sequencing. Statistically significant prognostic variables were identified using a multivariable Cox regression model and confirmed by L1/L2 regularized regressions.

RESULTS

Whole-genome sequencing revealed a commonly disrupted p53 pathway with nonredundant somatic structural variations (SVs) in TP53-related genes (TP63, TP73, and WWOX) and identified novel SVs facilitating immune evasion (DOCK8 and CD83). Integration of mutation and copy-number data expanded the repertoire of known PMBCL alterations (eg, ARID1A, P2RY8, and PLXNC1) with a previously unrecognized role for epigenetic/chromatin modifiers. Multivariable analysis identified six genetic lesions with significant prognostic impact. CD58 mutations (31%) showed the strongest association with worse PFS (hazard ratio [HR], 2.52 [95% CI, 1.50 to 4.21]; P < .001) and overall survival (HR, 2.33 [95% CI, 1.14 to 4.76]; P = .02). IPI high-risk patients with mutated CD58 demonstrated a particularly poor prognosis, with 5-year PFS and OS rates of 41% and 58%, respectively. The adverse prognostic significance of the CD58 mutation status was predominantly observed in patients treated with nonintensified regimens, indicating that dose intensification may, to some extent, mitigate the impact of this high-risk marker. By contrast, DUSP2-mutated patients (24%) displayed durable responses (PFS: HR, 0.2 [95% CI, 0.07 to 0.55]; P = .002) and prolonged OS (HR, 0.11 [95% CI, 0.01 to 0.78]; P = .028). Upon CHOP-like treatment, these patients had very favorable outcome, with 5-year PFS and OS rates of 93% and 98%, respectively.

CONCLUSION

This large-scale genomic characterization of PMBCL identified novel treatment targets and genetic lesions for refined risk stratification. DUSP2 and CD58 mutation analyses may guide treatment decisions between rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone and dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, doxorubicin, and rituximab.